We propose a new index for predicting the optimum layout of noise sources, that is designed to improve the communication performance of digital wireless equipment. In our previous studies, we developed a design method for optimizing the layout of a noise source using the correlation between the magnetic field distribution of the noise source and that of the antenna. However, this method does not allow easy comparison between different items of equipment. In this paper, we quantitatively and visually propose a new index that can predict the signal bit error rate by using the antenna interference power, obtained from the weighted magnetic field product that has been calculated from the magnetic field distributions of the noise source and the antenna. We have confirmed that the optimal layout of the noise source can be predicted using our proposal method in digital wireless equipment to minimize intra-EMC. We have further discovered a new index in which the optimal layout of the noise source can be found in contour formatted figures with good visibility.
Radar cross section (RCS) is one of important EM properties of radar targets. Its measurement requires long distance to obtain far-field characteristics in higher frequency range such as X-band. Planar scanning near-field measurement combined with near-field far-field (NF-FF) transformation is realized by simple measurement system. However, scan area truncation of planar scanning often cause intolerable error for predicted RCS. In this paper, the accuracy of NF-FF transformation technique based on fast multipole method (FMM) with scan area of planar scanning is investigated.
In this paper we analyze the uncertainty in measurement when assessing the exposure levels of the general public to RF electromagnetic fields (EMFs) from AM broadcasting transmitters. The purpose of measurement was to evaluate whether human exposure levels are in compliance (or not) with protection guidelines. Six sources of uncertainty were selected, and in order to allow for the propagation characteristics of the middle frequency range, the uncertainties of both the electric and magnetic fields were evaluated. Estimated uncertainties were identical to ±2.34 dB.
In this paper, a three level scheduling scheme is proposed for Long Term Evolution (LTE) network to enhance the cell throughput while maintaining fairness among User Equipments (UE). At initial level, the users with good channel conditions are scheduled that result in increase in cell throughput. At next level, the users with maximum delay requirements are allocated and at last level the users with long buffer queue are scheduled to maintain fairness among users. The proposed scheme is compared with traditional scheduling algorithms and validated by means of simulation results.
Evaluating network reliability is essential for network management. In the case that the failure probabilities of nodes and links change in an evaluation, iterative calculation of the reliability is required. In large networks, however, this calculation takes considerable time; thus, iterative calculation cannot be done within a practical amount of time. In this paper, we present a method for generating network reliability formulas that is based on the reliability calculation method with binary decision diagrams (BDD). We show that the time taken to calculate reliability can be reduced by the formula expression in some orders of magnitude compared with the conventional BDD calculation method, which excludes the overhead of formula generation.
Aiming for satisfying the requirement on quality of experience (QoE) for many important applications, we proposed a QoE-oriented WLAN which employs channel access permission control and dynamic network reconfiguration. For practical system deployment, it is important to assess the upper performance limit of the system. This letter introduces a metric “effective area throughput” (EAT): it is the area throughput summed up among the applications which achieve the throughput for satisfying their QoE requirements. This letter then derives the maximum expected EAT of the QoE-oriented WLAN based on a random sampling method. Through numerical evaluation, it is confirmed that the proposed derivation method provides a valid expected EAT for WLAN with several tens of nodes in a tractable computational complexity. It is also confirmed that the QoE-oriented WLAN has potential to increase the EAT compared with the conventional WLAN.